We have four Kyocera
that were bought and installed in 1998. Up until this week, they have worked flawlessly without a thought given to them.
One of the panels
has ceased providing current
. Here is the problem:
1. Voc across the leads is 21V as expected.
2. Isc is zero.
3. Vpm is 17.4V as expected
4. Ipm is zero.
Here is what I have found:
1. There are 6 bypass diodes arranged in two banks of three. The panel cells appear to be divided in half with these. All diodes test OK.
2. If I put a jumper wire across one bank of diodes, no change in output occurs.
3. If I put a jumper across the other bank, a lot of current
flows back INTO the panel.
I suspect I have an internal open or short circuit in one half of the panel, or where that half feeds its diode bank. Nothing is obvious from the foil traces that can be seen on top, and the bottom is all potted and sealed.
Anyone have any ideas?